Cancer remains one of the most deadly threats to human health. In the U.S., cancer affects nearly 1.3 million new patients each year, and is the second leading cause of death after heart disease, accounting for approximately 1 in 4 deaths. It is also predicted that cancer may surpass cardiovascular diseases as the number one cause of death within 5 years. Solid tumors are responsible for most of those deaths. Although there have been significant advances in the medical treatment of certain cancers, the overall 5-year survival rate for all cancers has improved only by about 10% in the past 20 years. Cancers, or malignant tumors, metastasize and grow rapidly in an uncontrolled manner, making timely detection and treatment extremely difficult. Furthermore, cancers can arise from almost any tissue in the body through malignant transformation of one or a few normal cells within the tissue, and each type of cancer with particular tissue origin differs from the others.
Current methods of cancer treatment are relatively non-selective. Surgery removes the diseased tissue; radiotherapy shrinks solid tumors; and chemotherapy kills rapidly dividing cells. Chemotherapy, in particular, results in numerous side effects, in some cases so severe as to limit the dosage that can be given and thus preclude the use of potentially effective drugs. Moreover, cancers often develop resistance to chemotherapeutic drugs.
Thus, there is an urgent need for more specific and more effective cancer therapies.
EGFR was cloned as 55 kD of I type membrane protein that belong to an immunoglobulin family (The EMBO Journal (1992), vol. 11, issue 11, p. 3887-3895, JP5336973, JP7291996). Human EGFR cDNA is composed of the base sequence shown in EMBL/GenBank Acc. No. NM005018 and mouse EGFR cDNA is composed of the base sequence shown in Acc. No. X67914, and those expressions are observed when thymus cells differentiate from CD4−CD8− cell into CD4+CD8+ cell (International Immunology (1996), vol. 18, issue 5, p. 773-780., J. Experimental Med. (2000), vol. 191, issue 5, p. 891-898.). It is reported that EGFR expression in periphery is observed in myeloid cells including T cells or B lymphocytes activated by stimulation from antigen receptors, or activated macrophages (International Immunology (1996), vol. 18, issue 5, p. 765-772.).